thunderbolt: Expand controller name in tb_switch_is_xy()

For a casual reader tb_switch_is_cr() does not tell much so instead
spell out the full controller name in the function name. For example
tb_switch_is_cr() becomes tb_switch_is_cactus_ridge() which is easier
to understand.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>